{NORTHERN PACIFIC IN THE PAST 
97 
I have endeavoured to show in this chapter how the more 
striking instances of relationship among the animals of Asia 
and North America can be explained, how they arose and 
under what climatic conditions. That Alaska was once joined 
by land to the opposite shore of Asia has been almost uni¬ 
versally acknowledged by biologists and geologists. But for 
our purpose we required something more definite than a state¬ 
ment such as that of Professor Heilprin,* “ it appears likely 
that the bears, swine, oxen, sheep, antelopes and elephants 
originated in the Old World, whence they were transplanted, 
by way of some land connection existing in the north* into 
the New World.” Even Dr. Arldt’s f remark, “the bridge 
between Asia and North America remained until the Glacial 
Period,” is too vague. I think I have brought together suffi¬ 
cient data to show that a land connection existed in the 
region of Bering Strait during Pliocene times until the com¬ 
mencement, or perhaps until the end, of the early part of the 
Pleistocene Period. As far as I know, the only fact that can be 
brought forward against such an assumption is the discovery 
by Dr. Dali $ of marine gravels at Nome, in Alaska, contain¬ 
ing shells which he believed to be of Pliocene Age. Consider¬ 
ing, on the other hand, that the gravels in question only con¬ 
tained one distinct species, it is quite possible that they may 
not be so old as Dr. Dali thinks. And even if their Pliocene 
age should be established by further researches, it only proves 
that the land connection was not so wide as we are apt to; 
believe. These gravels do not disprove the existence of the 
land bridge, for Nome is situated to the south of Bering Strait 
on the shores of the Bering Sea. 
I have adduced testimony showing that Alaska, not only in 
Pliocene times, but also during part of the Pleistocene Period, 
had a comparatively mild climate. Many of the larger 
mammals seem to have become exterminated within more 
recent times owing to a change of climate. There is no indi¬ 
cation of any wholesale destruction of the fauna during the 
Glacial Epoch followed by a recent introduction from the 
* Heilprin, A., “ Geographical Distribution of Animals,” p. 179. 
t Arldt, Th., “ Entwicklung der Kontinente,” p. 293. 
f Dali, W. H., “ Climatic Conditions at Nome,” p 457. 
L.A. 
H 
